62012-51-5Relevant academic research and scientific papers
Powerful fluoroalkoxy molybdenum(V) reagent for selective oxidative arene coupling reaction
Schubert, Moritz,Leppin, Jana,Wehming, Kathrin,Schollmeyer, Dieter,Heinze, Katja,Waldvogel, Siegfried R.
, p. 2494 - 2497 (2014)
We introduce the novel fluoroalkoxy molybdenum(V) reagent 1 which has superior reactivity and selectivity in comparison to MoCl5 or the MoCl5/TiCl4 reagent mixture in the oxidative coupling reactions of aryls. Common side reactions, such as chlorination and/or oligomer formation, are drastically diminished creating a powerful and useful reagent for oxidative coupling. Theoretical treatment of the reagent interaction with 1,2-dimethoxybenzene-type substrates indicates an inner-sphere electron transfer followed by a radical cationic reaction pathway for the oxidative-coupling process. EPR spectroscopic and electrochemical studies, X-ray analyses, computational investigations, and the experimental scope provide a highly consistent picture. The substitution of chlorido ligands by hexafluoroisopropoxido moieties seems to boost both the reactivity and selectivity of the metal center which might be applied to other reagents as well. Wait a Mo: A novel molybdenum(V) reagent (see scheme) is superior to the performance of MoCl5 in the oxidative coupling reaction of aryls leading to less by-products and significantly increased yields. Copyright
Oxidative Coupling Reactions Using Silica-Bound Ferric Chloride
Jempty, Thomas C.,Miller, Larry L.,Mazur, Yehuda
, p. 749 - 751 (1980)
Silica-bound ferric chloride serves as an oxidant for phenols and phenol ethers, leading to coupling of the aromatic rings.
About the selectivity and reactivity of active nickel electrodes in C-C coupling reactions
Beil, Sebastian B.,Bomm, Alexander,Breiner, Manuel,Holtkamp, Michael,Karst, Uwe,Müller, Timo,Schüll, Aaron,Schade, Wolfgang,Schollmeyer, Dieter,Schulz, Lara,Waldvogel, Siegfried R.
, p. 14249 - 14253 (2020/04/23)
Active anodes which are operating in highly stable protic media such as 1,1,1,3,3,3-hexafluoroisopropanol are rare. Nickel forms, within this unique solvent, a non-sacrificial active anode at constant current conditions, which is superior to the reported powerful molybdenum system. The reactivity for dehydrogenative coupling reactions of this novel active anode increases when the electrolyte is not stirred during electrolysis. Besides the aryl-aryl coupling, a dehydrogenative arylation reaction of benzylic nitriles was found while stirring the mixture providing quick access to synthetically useful building blocks.
Carbocatalytic Oxidative Dehydrogenative Couplings of (Hetero)Aryls by Oxidized Multi-Walled Carbon Nanotubes in Liquid Phase
Wirtanen, Tom,Aikonen, Santeri,Muuronen, Mikko,Melchionna, Michele,Kemell, Marianna,Davodi, Fatemeh,Kallio, Tanja,Hu, Tao,Helaja, Juho
supporting information, p. 12288 - 12293 (2019/09/06)
HNO3-oxidized carbon nanotubes catalyze oxidative dehydrogenative (ODH) carbon–carbon bond formation between electron-rich (hetero)aryls with O2 as a terminal oxidant. The recyclable carbocatalytic method provides a convenient and an operationally easy synthetic protocol for accessing various benzofused homodimers, biaryls, triphenylenes, and related benzofused heteroaryls that are highly useful frameworks for material chemistry applications. Carbonyls/quinones are the catalytically active site of the carbocatalyst as indicated by model compounds and titration experiments. Further investigations of the reaction mechanism with a combination of experimental and DFT methods support the competing nature of acid-catalyzed and radical cationic ODHs, and indicate that both mechanisms operate with the current material.
Mild, Fast, and Easy to Conduct MoCl5-Mediated Dehydrogenative Coupling Reactions in Flow
Beil, Sebastian B.,Uecker, Ise,Franzmann, Peter,Müller, Timo,Waldvogel, Siegfried R.
supporting information, p. 4107 - 4110 (2018/07/15)
A convenient and straightforward approach to performing oxidative coupling reactions in flow is presented. A collection of electron-rich benzene derivatives was subjected to this protocol, and the distinct utility of molybdenum pentachloride (MoCl5) is established. Using this unexplored protocol, biphenyls could be obtained in 21-91% isolated yield. This simple protocol opens a new chapter in reagent-mediated dehydrogenative coupling reactions, and yields are compared to classical approaches.
Active Molybdenum-Based Anode for Dehydrogenative Coupling Reactions
Beil, Sebastian B.,Müller, Timo,Sillart, Sydney B.,Franzmann, Peter,Bomm, Alexander,Holtkamp, Michael,Karst, Uwe,Schade, Wolfgang,Waldvogel, Siegfried R.
supporting information, p. 2450 - 2454 (2018/02/09)
A new and powerful active anode system that can be operated in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) has been discovered. In HFIP the molybdenum anode forms a compact, conductive, and electroactive layer of higher-valent molybdenum species. This system can replace powerful but stoichiometrically required MoV reagents for the dehydrogenative coupling of aryls. This electrolytic reaction is more sustainable and allows the conversion of a broad scope of activated arenes.
METHOD FOR OXIDATIVE COUPLING OF AROMA COMPOUND, OXIDIZING AGENT USED IN THIS METHOD, AND OXIDIZED FLAKED GRAPHITE USED AS OXIDIZING AGENT
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Paragraph 0023; 0024; 0049-0052, (2017/03/25)
PROBLEM TO BE SOLVED: To provide a method for oxidative coupling of aroma compounds using an oxidizing agent used at the time of oxidative coupling of aroma compounds which facilitates separation of residues of the oxidizing agent as a by-product produced together with a target coupling product and can reduce by-product disposal cost, and an oxidizing agent used in the method and oxidized flaked graphite used as an oxidizing agent. SOLUTION: In a method for oxidatively coupling aromatic compounds by adding an oxidizing agent to a solution in which the aromatic compounds have been dissolved to cause an oxidative coupling reaction, oxidized flaked graphite flaked by oxidizing graphite is used as the oxidizing agent. More particularly, the oxidized flaked graphite is produced by adding graphite to a mixed solution of sodium nitrate, sulfuric acid, and potassium permanganate. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2017,JPOandINPIT
Carbocatalytic reductive coupling reactions: Via electron transfer from graphene to aryldiazonium salt
Morimoto, Naoki,Morioku, Kumika,Suzuki, Hideyuki,Nakai, Yumi,Nishina, Yuta
supporting information, p. 7226 - 7229 (2017/07/11)
A reductive coupling reaction using two-dimensional nanocarbon, i.e., reduced graphene oxide (rGO), as a carbocatalyst and/or a reaction initiator was developed. The radical species on the rGO played an important role in the coupling reaction.
Intramolecular dehydrogenative coupling of 2,3-diaryl acrylic compounds: Access to substituted phenanthrenes
Gupta, Vijay,Rao, V. U. Bhaskara,Das, Tamal,Vanka, Kumar,Singh, Ravi P.
, p. 5663 - 5669 (2016/07/14)
A simple, facile, and environmentally benign intramolecular dehydrogenative coupling of various 1,2-diarylethylenes for the synthesis of phenanthrenes in excellent yield has been described. This new methodology uses ceric ammonium nitrate (CAN) as a promoter at room temperature and has been extended to intermolecular synthesis of biaryl compounds. The electron transfer from methoxyarene to cerium leads to cationic radical formation, which further proceeds to intramolecular coupling. Preliminary mechanistic investigation by EPR spectroscopy and density functional theory calculation suggested a similar view.
An economical and environmentally friendly oxidative biaryl coupling promoted by activated MnO2
Yang, Jingjing,Sun, Shutao,Zeng, Ziyu,Zheng, Hongbo,Li, Wei,Lou, Hongxiang,Liu, Lei
, p. 7774 - 7779 (2014/12/10)
An activated manganese dioxide (MnO2)-BF3·OEt2 oxidation system was developed to efficiently mediate the intramolecular as well as intermolecular biaryl coupling. The oxidative coupling proceeds smoothly at ambient temperature to deliver the corresponding five- to eight-membered tricyclic products in good to excellent yields. The employment of the combination of MnO2 and BF3·OEt2 is attractive on the basis of economical and environmental issues.
